Re: If you want to be invisible on a car lot...

Bill Baka <bbaka@xxxxxxxx> wrote:

Mark Hickey wrote:
Bill Baka <bbaka@xxxxxxxx> wrote:

Real wheel drive with a stick for me. Those I can work on for fun and
mileage. A little gear change can turn a 25 MPG pig into a 40 MPG car.


Bill, there are times when I'm sure you have a problem with the laws
of physics.

This is one of those times.

You can gear a car to reduce the engine RPM by 1.4 times, but why
would it not require more fuel per revolution to produce the same
amount of work?

Answer that one and you've solved the world's energy crisis (and
disproved Newton).

Mark,
In this case I can really suggest you think before you post.
Engine wear and energy wasted work as at least the square of the speed.
You don't think those pistons want to go up and down at 3,000 RPM, do
you? It takes more energy to drive the pistons than the car sometimes.

Bill, you're just wrong. Period.

Internal engine friction is similar to hub friction on a bike. It's
significant, but you're not going to decrease your energy requirements
for cruising at highway speeds by 50% by eliminating it. If what you
said was true, the gas mileage of a Mustang and an F-350 would be
similar since they have the same engine - though presumably the truck
would have higher gearing, so it would get better mileage in your
universe.

As with a bike, the VAST majority of energy goes into overcoming
aerodynamic resistance. It still takes the same amount of work to do
that, no matter what speed the engine is turning. To get the benefit
you're claiming, the aerodynamic loading would have to be almost
negligible.

Mark Hickey
Habanero Cycles
http://www.habcycles.com
Home of the $795 ti frame
.

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